The present invention relates to non-woven cloth products and, in particular, it concerns a method for producing abrasive non-woven cloth, and the cloth resulting from this method.
Non-woven cloth (fabric) is used for an ever-growing range of products and applications. In particular, the constant trend towards use of disposable products has lead to huge growth in the market for non-woven materials, and has seen non-woven cloths being adapted as a cost-effective basis for many new products.
Types of non-woven cloth may be classified in many ways, for example, according to the type and gauge of fibers used, the laying technique for forming a web, or the linking technique for uniting the fibers into a cloth. Examples of classes of cloth production techniques to which the present invention is believed to be applicable include, but are not limited to, hotmelt, wet-laid and dry-laid water entanglement, thermo-bonding, air-through thermo-bonding and chemical bonding.
For certain applications, it is desirable to provide various degrees of abrasivity to non-woven cloth. This ranges from very mild abrasive properties used for facial cleansing or skin treatment through to highly abrasive scouring pads used for cleaning kitchen utensils. The required abrasive properties are generally achieved by use of thick gauge fibers which inherently exhibit the required abrasivity.
U.S. Pat. No. 5,786,065 to Annis et al. describes a process for producing an abrasive non-woven material from an initially non-abrasive precursor by heating the cloth which includes between 10% and 50% by weight of thermoplastic fibers to near the melting point of the thermoplastic fibers so that they contract to form nodules. These nodules impart abrasive properties to one planar surface of the material. Differential properties between the two surfaces is achieved by ensuring a gradient in the proportion of the thermoplastic fibers through the initial cloth.
According to the teachings of Annis et al., the abrasivity is a function of the size of the nodules which is, itself, a function of the gauge of thermoplastic fibers used in the precursor material. From the examples quoted, Annis et al. implies that effective high abrasivity may be achieved by using fiber size in the range of 10-55 denier, corresponding to about 11-60 grams per 10,000 meters length of fiber (referred to as “decitex” or “d-tex”). This thickness of fiber necessarily imparts a noticeable coarseness and, after heat treatment, a degree of stiffness to the resulting cloth. In all cases, the surfaces of the material are clearly stated to be planar.
There is therefore a need for a production method and corresponding product which would provide a controllable degree of abrasivity of a non-woven cloth using low-gauge fibers and while maintaining a high degree of flexibility in the cloth.